Bollettino valanghe

Mount Shasta

Mount Shasta Avalanche Center
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Pericolo valanghe

Mon
Alta quota
4 · Forte
Limite del bosco
4 · Forte
Sotto il limite
3 · Marcato
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In sintesi

Avoid traveling in the backcountry today. Very large natural avalanches are likely and your odds of triggering an avalanche are even higher. With several feet of new snow and intense wind, avalanches are possible on all aspects and elevations. Being on, near, or beneath slopes greater than 30° will be dangerous.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    1–3

    West, southwest wind and days of snowfall make wind slab avalanches our primary problem today. Over the past 24 hours, wind speeds averaged 16 mph near treeline. Today, the wind will be much more intense and capable of moving large amounts of snow onto leeward aspects, even down into lower elevations.

    You'll be most likely to find these wind slabs on predominately north, northeast, east, and southeast aspects. With that being said, the leeward side of trees and other terrain features are catchment areas, so you could encounter a wind slab on any side of the compass in complex terrain. 

    There is two to three feet of new snow on the ground since Wednesday and another two to three feet expected in the next 24 hours. This means that a wind slab avalanche today could be several feet deep and may not be survivable.

    Avoid traveling on any of the shaded aspects of the compass rose and keep an eye out for drifting, shooting cracks, and collapsing.

    (3/14/2025)

    Wind slab avalanche crown and flank initiated by cornice failure on an east aspect of Gray Butte

    Photo: Mount Shasta Avalanche Center

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2.5

    There's two feet of snow in the forecast today and as a result storm slab avalanches are likely on all aspects below and near treeline. With warmer temperatures over the past 24 hours there is a slightly upside-down snow structure, increasing the possibility of storm slab activity. 

    These slabs could be reactive to the weight of a rider, and if triggered, could fail large enough to bury a person. Avoid travel on slopes greater than 30° and watch for signs of instability: natural avalanches, cracking, and/or collapsing. 

    (1/20/2024)

    Soft Slab Avalanche

    Photo: Samuel Clairmont

Avalanche Discussion

Travel in the backcountry today will be dangerous and we do not recommend it. If you must go, bring an experienced partner and avoid being on, near, or beneath steep slopes greater than 30°. 

There are a couple of different weak layers in the snowpack:

  • A one to three centimeter thick layer of graupel, buried two to four feet deep. We confirmed this layer's presence across all aspects in the Gray Butte area.
  • The other weak layer is a four centimeter thick layer of rounding facets. We found this layer present below treeline on northerly aspects in the Castle Lake Creek drainage.

Both layers are at the new/old snow interface that was buried on Wednesday and continue to produce propagation in stability tests. So far, this layer has produced no observable avalanches. Additional loading from new snow and powerful winds could tip the scales on this weak layer, producing an avalanche several feet deep and propagating wide. 

We try, but we can't be everywhere at once. If you get out in the woods, please submit your findings on our public observation page.

The Everitt Memorial Highway and Castle Lake Road is CLOSED. For further road information: https://www.co.siskiyou.ca.us/publicworks/page/closures-and-delays

Regioni coperte